3-Card Major Raises

Nearly all of bidding systems with 5-card majors prefer a delayed 3-card raise if responder has an invitational hand, typically 10-12 points. The most common route they follow is to bid 1NT first and then rebid 3M if possible. So, following auctions crop up time after time:

1 ♠ - 1NT
2 ♦ - 3 ♠

1 ♥ - 1NT
2 ♣ - 3 ♥

etc.

I can sympathize giving a belated 3-card raise but what I do not understand is why we delay it if partner's rebid will not change our own rebid in the first place. Depending on partner's second bid, following can happen:

• our hand improves,
• it gets worse,
• it does not change,
• we discover a new and better fit.

Interestingly, most of these systems advocate a single response: raise to 3M; 1M-1NT-2x-3M. Don't you think it is wasteful? Regardless of what opener says, we raise to 3. If you do not have a set of responses catering to all or at least some of the options above, then I think it is better to raise the major immediately, presumably using 3 of a minor or some similar mechanism. The competition will know less about opener's hand if nothing else. Advantage? Your 1NT response will not contain 3 cards in opener's suit. But  if you insist giving delayed 3-card raises, you might as well start thinking about how to improve your 1NT structure so that opener's rebid (and effort) really matters.